The inventions concerns a sealing arrangement for a rotary valve member arranged within the combustion chamber of an internal combustion engine, the rotary valve member provided for opening and closing gas inlet and outlet channels provided in the cylinder head, the sealing arrangement comprising a hollow substantially cylindrical sealing body arranged axially displaceable in each one of the gas channels, the sealing body by a sealing force being urged in the direction of the rotary valve member and held in sealing contact therewith.
U.S. Pat. No. 2,283,594 shows a sealing arrangement of this kind in which the sealing body is urged by a helical spring against the rotary valve having a conical sealing surface. The spring must be strong to overcome the maximum gas pressure and therefor for the most time during the working cycle is overdimensioned. The strong spring force results in forming flutes or marks in the sealing surfaces and therefore no long-time sealing effect is possible. Further an absolutely uniform contact of the sealing body along the whole periphery thereof is not possible because of non-uniform wear and different heat deformation in the peripheral areas of the sealing body.
From German Pat. No. 758,968 it is known to urge the sealing body in contact with the ball-shaped inside surface of the rotary valve by gas pressure which is admitted to the front face of the sealing member facing the rotary valve. The sealing member therefore is urged outwardly. Further it is mounted for rotation about the axis of the gas channel. Although this concept is advantageous with respect to the non-rotatable sealing body the disadvantage consists in that the sealing body lies inside of the rotary valve member within the combustion chamber and is exposed to the hot gas. Therefor the sealing body will be warped upon heat effect and because of carbon deposit becomes seized.
German Pat. No. 904,959 shows a ball-shaped rotary valve in the gas channel of which the sealing body is mounted for rotation and urged outwards by the gas pressure against the inside surface of the cylinder head. Because the same disadvantages even to a greater extent exist no long-life sealing can be achieved.